1. Field of the Invention
This invention relates to light barriers or shields. More particularly, it relates to devices for directing and shielding the light from light emitting diodes (LED's) that are mounted on printed circuit boards (PCB's).
2. Description of the Related Art
LED's are particularly suited for use as status indicators for various electronic circuits and systems. They are small, relatively inexpensive, have modest power requirements, produce little heat and have a long working life. LED's are available from a variety of sources in packages which permit direct mounting to a printed wiring board (PWB). However, since a PWB or PCB is typically mounted within a chassis of some sort, LED's on the PCB are usually not directly viewable by the user of the device.
In the past, light pipes comprised of rods or bundles of fibers of clear plastic or glass have been used to direct the light from PCB-mounted LED's to lenses or windows on, for example, the front panel of an electronic device where they may be viewed by the user. However, there are a number of disadvantages associated with this system: the light pipes must be aligned with both the LED and the viewing lens or window; and, the light from adjacent LED's can “bleed over” into an adjoining light pipe producing indefinite indications to the user. Moreover, light pipes are relatively costly and labor-intensive to install. The present invention solves these problems in a particularly efficient and cost-effective way.